proc: use __auto_type more

Switch away from quite chatty declarations using typeof_member().

In theory this is faster to compile too because there is no macro
expansion and there is less type checking.

Link: https://lkml.kernel.org/r/81bf02fd-8724-4f4d-a2bb-c59620b7d716@p183
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Alexey Dobriyan

fs/proc/inode.c

@@ -303,9 +303,7 @@ static ssize_t proc_reg_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 
 static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos)
 {
-	typeof_member(struct proc_ops, proc_read) read;
-
-	read = pde->proc_ops->proc_read;
+	__auto_type read = pde->proc_ops->proc_read;
 	if (read)
 		return read(file, buf, count, ppos);
 	return -EIO;
@@ -327,9 +325,7 @@ static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count,
 
 static ssize_t pde_write(struct proc_dir_entry *pde, struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 {
-	typeof_member(struct proc_ops, proc_write) write;
-
-	write = pde->proc_ops->proc_write;
+	__auto_type write = pde->proc_ops->proc_write;
 	if (write)
 		return write(file, buf, count, ppos);
 	return -EIO;
@@ -351,9 +347,7 @@ static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t
 
 static __poll_t pde_poll(struct proc_dir_entry *pde, struct file *file, struct poll_table_struct *pts)
 {
-	typeof_member(struct proc_ops, proc_poll) poll;
-
-	poll = pde->proc_ops->proc_poll;
+	__auto_type poll = pde->proc_ops->proc_poll;
 	if (poll)
 		return poll(file, pts);
 	return DEFAULT_POLLMASK;
@@ -375,9 +369,7 @@ static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
 
 static long pde_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
 {
-	typeof_member(struct proc_ops, proc_ioctl) ioctl;
-
-	ioctl = pde->proc_ops->proc_ioctl;
+	__auto_type ioctl = pde->proc_ops->proc_ioctl;
 	if (ioctl)
 		return ioctl(file, cmd, arg);
 	return -ENOTTY;
@@ -400,9 +392,7 @@ static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigne
 #ifdef CONFIG_COMPAT
 static long pde_compat_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
 {
-	typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl;
-
-	compat_ioctl = pde->proc_ops->proc_compat_ioctl;
+	__auto_type compat_ioctl = pde->proc_ops->proc_compat_ioctl;
 	if (compat_ioctl)
 		return compat_ioctl(file, cmd, arg);
 	return -ENOTTY;
@@ -424,9 +414,7 @@ static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned
 
 static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma)
 {
-	typeof_member(struct proc_ops, proc_mmap) mmap;
-
-	mmap = pde->proc_ops->proc_mmap;
+	__auto_type mmap = pde->proc_ops->proc_mmap;
 	if (mmap)
 		return mmap(file, vma);
 	return -EIO;
@@ -483,7 +471,6 @@ static int proc_reg_open(struct inode *inode, struct file *file)
 	struct proc_dir_entry *pde = PDE(inode);
 	int rv = 0;
 	typeof_member(struct proc_ops, proc_open) open;
-	typeof_member(struct proc_ops, proc_release) release;
 	struct pde_opener *pdeo;
 
 	if (!pde->proc_ops->proc_lseek)
@@ -510,7 +497,7 @@ static int proc_reg_open(struct inode *inode, struct file *file)
 	if (!use_pde(pde))
 		return -ENOENT;
 
-	release = pde->proc_ops->proc_release;
+	__auto_type release = pde->proc_ops->proc_release;
 	if (release) {
 		pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
 		if (!pdeo) {
@@ -547,9 +534,7 @@ static int proc_reg_release(struct inode *inode, struct file *file)
 	struct pde_opener *pdeo;
 
 	if (pde_is_permanent(pde)) {
-		typeof_member(struct proc_ops, proc_release) release;
-
-		release = pde->proc_ops->proc_release;
+		__auto_type release = pde->proc_ops->proc_release;
 		if (release) {
 			return release(inode, file);
 		}